Process for the industrial preparation of 4-chloro-3-sulfamoyl-n-(2,3-dihydro-2-methyl-1h-indol-1-yl)benzamide

Abstract

The invention relates to a new process for the industrial preparation of 4-chloro-3-sulfamoyl-N-(2,3-dihydro-2-methyl-1H-indol-1-yl)benzamide from monochloramine and 2,3-dihydro-2-methyl-1H-indole.

I claim: 
     
       1. A process for the preparation of 4-chloro-3-sulfamoyl-N-(2,3-dihydro-2-methyl-1H-indol-1-yl)-benzamide, the compound of formula I: ##STR5## wherein a solution of ammonium hydroxide and ammonium chloride is reacted with an aqueous solution of sodium hypochlorite at a temperature of between -10° C. and -5° C. in an alkaline medium, and the monochloramine thereby formed is reacted with 2,3-dihydro-2-methyl-1H-indole, the compound of formula II: ##STR6## in solution in a low molecular weight (C 1  -C 5 ) aliphatic alcohol, at a temperature of between 30° C. and 80° C. and in an alkaline medium,   and the 1-amino-2,3-dihydro-2-methyl-1H-indole, the compound of formula III: ##STR7##  thereby formed, is thereafter separated and reacted in the form of a base or salt, in solution in tetrahydrofuran or in an alcoholic medium and in the presence of an acid-acceptor with 4-chloro-3-sulfamoylbenzoyl chloride, the compound of the formula IV: ##STR8## at a temperature of between 20° C. and 30° C. to form the compound of formula I.   
     
     
       2. The process as claimed in claim 1, wherein the 2,3-dihydro-2-methyl-1H-indole is in solution in ethanol. 
     
     
       3. The process as claimed in claim 1, wherein the concentration of the alcoholic solution of 2,3-dihydro--methyl-1H-indole is from 0.5 to 1 mole/1. 
     
     
       4. The process as claimed in claim 1, wherein the reaction of monochloramine with 2,3-dihydro-2-methyl-1H-indole is carried out at a pH of between 13 and 14. 
     
     
       5. The process as claimed in claim 1, wherein the reaction of monochloramine with 2,3-dihydro-2-methyl-1H-indole is carried out at a temperature of between 40 and 5° C.. 
     
     
       6. The process as claimed in claim 1, wherein -amino-2,3-dihydro-2-methyl-1H-indole is reacted in the form of a hydrochloride or mesylate with 4-chloro-3-sulfamoylbenzoyl chloride.